Generally, a silver halide photographic light-sensitive material is processed by developing, fixing, washing and other processes for black-and-white light-sensitive materials or color developing, bleach-fixing (or bleaching and fixing), washing, stabilizing and other processes for color light-sensitive materials. In photographic processes wherein a large amount of light-sensitive material is processed, it is a common practice to replenish the components consumed during the processing and remove the components dissolving from the light-sensitive material into the processing solution to keep constant the processing solution component balance and hence to maintain constant processing solution performance. Specifically, a replenisher is supplied to the processing solution and a part of the processing solution is discharged and disposed of as a waste liquid from the processing system to remove the dissolved components.
However, such photographic processing waste liquids exert very high pollution load on the environment.
As a solution to the problem of waste liquid of photographic treatment and water supply, Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 201442/1987 discloses a method wherein waste liquid is thermally evaporated under normal pressure and the resulting distillate is recycled, with a description that the distillate can be used as such to prepare a bleach-fixer. However, some secondary treatment is necessary before the thus-obtained distillate can be used as a solvent for color developer, stabilizer and other processing solutions. This method also proved undesirable from the viewpoint of work environmental hygiene because of malodor generation upon evaporative concentration.
Also, the same publication discloses that the distillate can be used as such to prepare a bleach-fixer. However, if the waste liquid is thermally evaporated under normal pressure, various waste liquid components and decomposition products accumulate in the distillate; the distillate cannot serve for practical use as a solvent or an evaporation compensator.
Also, Japanese Patent O.P.I. Publication No. 229688/1991 and other publications disclose a method of thermally evaporating photographic processing waste liquid by a pressure reducing means, which method certainly is almost free of malodor generation upon evaporative concentration, or considerably reduces the accumulation of waste liquid component decomposition products etc. in the distillate. However, when the distillate resulting from this method was used as a solvent or an evaporation compensator, there occurred image storage stability deterioration after processing, particularly yellow dye fading and increased yellow staining at high temperatures. Post-processing film staining and pre-drying squeeze roller staining were also demonstrated.